Tool actuating device

ABSTRACT

A tool actuating device to control both the speed and feed of the tool and to provide a preselected short period of time in which the tool dwells at its outermost extension before automatically being retracted.

United States Patent Inventor Richard E. Eckman Houston, Tex. Appl. No. 783,824 Filed Dec. 16, 1968 Patented Apr. 13, I971 Assignee Dreser Industries, Inc. Dallas, Tex.

TOOL ACTUATING DEVICE 13 Claims, 5 Drawing Figs.

US. Cl 408/9, 408/ 13 and 408/132 Int. Cl B23b 45/14, B23b 47/ l 8 Field of Search 77/1 3, 32.5, 32.8, 32.9, 34.7

[56] References Cited UNITED STATES PATENTS 3,487,729 1/1970 Juhasz et al 77/13 Primary Examiner-Francis S. Husar AttorneysRobert W. Mayer, Raymond T. Majesko, William E. Johnson, Jr., Roy L. Van Winkle, Eddie E. Scott and Daniel Rubin ABSTRACT: A tool actuating device to control both the speed and feed of the tool and to provide a preselected short period of time in which the tool dwells at its'outermost extension before automatically being retracted.

TOOL ACTUATING DEVICE SUMMARY The present invention relates to an improved tool actuating device for controlling the speed of rotation and the feed of a tool connected to the device.

An object of the present invention is to provide an improved tool actuating device for rotating a tool and feeding the tool axially to a preselected depth, stopping the feeding while the tool continues to rotate for a dwell period of preselected duration and thereafter automatically retracting the tool.

A further object of the present invention is to provide an improved tool actuating device for automatically controlling the speed and feed of a tool in which the tool may be manually controlled and providing in the automatic control a preselected dwell period at the most extended part of the tool travel before the tool is retracted.

Another object is to provide an improved tool actuating device in which the rate of rotation of the tool and the feed rate may be changed.

Still another object of the present invention is to provide an improved tool actuating device which automatically rotates and feeds a tool a preselected distance, stops the feeding for a preselected dwell period with the tool continuing to rotate and then retracts the tool at a rapid rate.

A still further object is to provide an improved tool actuat ing device in which the tool is fed at right angles to the device with an automatic stop providing a preselected dwell period at the outermost extension of the tool and thereafter rapid retraction of the tool.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the present in vention are hereinafter set forth and explained with reference to the drawings wherein:

FIG. I is an elevation view of one form of improved device of the present invention.

FIG. 2 is a partial cross-sectional view of the device shown in FIG. I with the motor, governor and part of the gear train omitted.

FIG. 3 is an elevation view of another form of the improved device of the present invention.

FIG. 4 is a partial cross-sectional view of the device shown in FIG. 3 with the motor, governor and part of the gear train omitted.

FIG. 5 is an elevation view of the clutch member used in the improved device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improved device of the present invention is adapted to control the actuation or working movement of a tool such as a drill. This device engages a drill, rotates the drill in the proper direction for drilling while feeding the drill into the workpiece. The device is provided with an automatic stop and reverse or retraction means which provides a dwell period of preselected duration before retraction of the tool commences. For example, in drilling the drill when it reaches its maximum extension may not have completed all of the hole to its desired depth and several revolutions of the drill without further feeding are desirable to cleanup and finish the bottom of the hole to the desired depth. The dwell period provided by the improved device allows this cleanup and finishing of the hole.

The form of the device of the present invention as shown in FIG. 1 includes a housing H in which a prime mover such as an air driven motor (not shown) is contained together with the usual governor (not shown) and planetary gear system (not shown) driving a gear train. The control lever is used to control the operation of the motor. The motor drives the gear train illustrated in FIG. 2 to rotate and feed the spindle 12. The spindle 12 extends through the housing H at right angles thereto and is provided with a stop collar 14 which may be adjustably positioned on the upper end of spindle 12 to limit the feeding extension of the spindle 12. Further, the spindle is provided with suitable means (bushing 15) for engaging a tool T. The housing H supports a suitable means such as sleeve 16 to engage the workpiece (not shown) on which the tool T is to perform work. The lever 18 and the button 20 are the manual controls provided to reverse the feeding or engage the feeding of the spindle 12, respectively.

This device as shown in FIG. 2 includes a gear train connecting between the planetary gear output to both rotate and feed the spindle 12. The bevel gear 22 is connected to the planetary gear drive from the motor and forms a part of the gear train which is supported in the housing H and connected to rotate spindle gear 24. This gear train includes the bevel gear 26 which is connected on shaft 28 by the hex 30, the spur gear 32 on shaft 28 driving the idler gear 34, and the clutch gear 36 which is driven by the idler gear 34 and drives the spindle gear 24. Spindle gear 24 is secured to spindle 12 by having the inwardly projecting lugs 38 engaging in the axially extending external grooves 40 on spindle 12. Thus, whenever the motor is running the gear train connection causes the spindle l2 and any tool carried thereby to be rotating at a preselected speed. As can be seen from FIG. 2 all of the components of gear train are properly supported in housing H and provided with suitable bearings to minimize the friction.

Since it is also desired to cause the spindle l2 and tool T to be moved in an axial direction (feeding) at a definite rate in relation to the speed of rotation of the spindle 12, a feeding means is provided. This feeding means includes the feed gear 42 which has internal threads engaging with the external threads on the spindle 12, the clutch member 44 and the gear 46 engaging feed gear 42 and clutch member 44. It is generally preferred that the external threads on spindle 12 be left-hand threads of a preselected pitch which is determined as hereinafter explained. Clutch gear 36, clutch member 44 and gear 46 when in the position shown in FIG. 2 all rotate at the same rate. Gear 46 has one more tooth than clutch gear 36 and feed gear 42 has one less tooth than spindle gear 24 whereby feed gear 42 rotates slightly faster than spindle 12. Because of the left-hand threads on spindle 12, the faster rotation of feed gear 42 causes spindle 12 to feed downwardly through feed gear 42 and spindle gear 24. The feed of spindle 12 is thus determined by the rate of rotation of feed gear 42 with respect to spindle I2 and the pitch of the spindle threads.

In feeding tools it is desired that the tool be fed at a preselected rate to a preselected extension and then be automatically retracted. Additionally it is desirable if the tool can remain at such outermost extension while still rotating for a short period of time, herein called a dwell period. The stop collar 14 is adjustably positioned on the upper end of spindle l2 and is adapted to engage the thrust bearing 48 to stop the feeding of spindle I2. The thrust bearing 48 allows further rotation of collar I4 and spindle 12 but prevents axial movement of spindle 12 in the feeding direction. With further axial movement of spindle l2 stopped, the clutch means is provided to allow the clutch member 44 to disengage from clutch gear 36. The clutch member 44 is restrained from disengaging from clutch gear 36 by the engagement of ball 50 in detent 52 in button 20. In FIG. 2, this ball detent structure has been rotated from its position behind the button 20 to the position shown for clarity. The ball 50 is urged by the spring 54 into the detent 52 so that button 20 must be positively moved to allow clutch member 44 to disengage from clutch gear 36. Clutch member 44 is biased in the direction of disengagement from clutch gear 36 by the spring 56. The engaging teeth between clutch member 44 and clutch gear 36 are tapered at an angle so that as stop collar 14 prevents further feeding of spindle l2 and the clutch member 44 is caused to rotate at a different rate than the clutch gear 36, the clutch member 44 is slowly cammed by the tapered sides of these teeth out of engagement with the clutch gear 36. Several revolutions of the spindle 12 are required to complete this camming to the extent that spring 56 takes over and moves the clutch member 44 to its uppermost position.

The desired dwell is provided by the time taken to cam the clutch member 44 out of engagement with the clutch gear 36. The difference in the gear ratios between spindle gear 24 and clutch gear 36 and feed gear 42, gear 46 and clutch member 44 determines how many revolutions of spindle 12 are required before clutch member 44 has disengaged from clutch gear 36. This period is the dwell time of the unit and may be varied by changing the height of the camming teeth and the relative gear ratios.

In order to provide retraction of the tool T, the clutch member 44 includes the projections 58 extending upwardly on the upper end thereof and adapted to engage within the recesses 60 in housing H to prevent further rotation of clutch member 44, gear 46 and feed gear 42. When feed gear 42 is held against rotation and spindle 12 is rotated therein, the spindle 12 is retracted from its extended position at a relatively rapid rate, depending upon the pitch of the threads on spindle 12. Thus, the pitch of the threads on spindle 12 are preselected to provide the desired amount of feed per revolution of spindle l2 and also to provide the desired rate of retraction.

With the device illustrated in FIG. 2, the retraction of the spindle l2 and tool T may be accomplished manually by depressing the lever 18 to move button upwardly and allowing spring 56 to cause clutch member to disengage from clutch gear 36 and move into engagement with housing recesses 60. This movement causes retraction. The retraction movement may be stopped by depressing the button 20 or by stopping the motor by actuation of the lever 10.

The form of actuating device of the present invention illustrated in FIGS. 3 and 4 is similar to the device previously described in that it transmits the rotation provided by a prime mover such as an air motor through a gear train to both rotate the spindle and feed the spindle at right angles to the device. This device includes a motor, governor and planetary gear system (all not shown) withinthe housing H and the control lever 62 which controls the motor. The two spindle speed buttons 64 and 66 project from the housing H as do the two feed buttons 68 and 70. The spindle 72 extends through the housing H at right angles and is provided with external left-hand threads and longitudinally extending grooves 74. The stop collar 76 is adjustably secured to the spindle 72 to limit the feeding extension of the spindle 72. The details of construction of the gear train and the structure providing the change of spindle speed and feed are shown in FIG. 4.

The output from the motor and planetary gear system is delivered to the bevel gear 78 which is similar to the bevel gear 26 shown in FIG. 2. The gear train shown provides a direct drive connecting to the spindle gear 80 to rotate the spindle 72 with the drive connection having a particular gear ratio. In order to change the speed at which the spindle 72 rotates, the speed change assembly 82 is actuated to change the gear ratio of the drive to the spindle gear 80. The speed change assembly 82 is controlled by the buttons 64 and 66 as hereinafter explained. Further, the gear train is connected to drive the feed gear 84 so that the spindle 72 may be fed at one of two feed rates and also to allow the spindle 72 to have a dwell period as previously defined prior to automatic retraction. The feeding of the spindle 72 is controlled by the buttons 68 and 70 as hereinafter described.

With the speed change assembly 82 in the position illustrated in FIG. 4, the spindle gear 80 is driven from the bevel gear 78, the hex 86, shaft 88, spur gear 90, idler gear 92, through the speed change assembly 82, the idler gear 94, the gear 96 and the two clutch gears 98 and 100. The speed change assembly 82 includes the clutch gear 102 which is driven by idler gear 92, the sprag clutch 104 and the gear 106 which is connected to drive gear 94 when the clutch 104 drives gear 106. The sprag clutch 104 is of the type which allows slippage whenever the outer gear 106 is rotated faster than the inner clutch gear 102 but provides a driving connection between gear 102 and gear 106 when gear 106 is not rotating faster than gear 102. The speed change assembly 82 has all of its rotating members mounted on the shaft 108.

To change the gear ratio to spindle gear 80, the button 66 is pushed inwardly of the housing H. This causes the shaft 108 to shift upwardly moving button 64 outwardly of housing H and bringing clutch member 110 into engagement with clutch gear 102. Thus clutch member 110 is driven directly by clutch gear 102 and by its splined connection with gear 112 it drives the gear 96 at a faster rate than when the driving train to gear 96 was through the sprag clutch 104. Gear 106 which remains in engagement with gear 94 is driven at the greater rate of speed and therefore is free running with respect to gear 102 because of the nature of the sprag clutch 104 which allows the outer member to rotate free of the inner member whenever the outer member is rotating at a greater speed than the inner member.

Spindle gear is provided with lugs engaging in the grooves or keyways 74 in spindle 72 and thus the speed of rotation of spindle 72 is varied by changing the gear train ratio with the speed change assembly 82 as described. Whenever a lower spindle speed is desired, the button 64 is pushed causing clutch member to disengage from clutch gear 102 and thereby changing the drive train back through the sprag clutch 104.

Tool T supported in the bushing 114 on the lower end of spindle 72 rotates at the speed of spindle 72. It is generally desired that such tool T be fed at a preselected rate and that such rate be capable of being changed. For example, assuming that the tool T is a drill bit which tool is to function by first drilling a hole through a first workpiece and thereafter drill a hole in a second workpiece of dissimilar material. Normally the preferred speed and feed of a drill will vary with different materials. With the improved device of the present invention shown in FIGS. 3 and 4, this change of feed and speed may be achieved by manipulation of the buttons 64, 66, 68 and 70.

The feed is determined by which of the clutch assemblies 118 and 120 is engaged. With the clutch assemblies 118 and 120 positioned as shown in FIG. 4, clutch assembly 118 is disengaged and clutch assembly 120 is engaged to drive the feed gear 84. With the clutch assembly 120 engaged, the clutch member 122 engages clutch gear 100 which is in the gear train driving the spindle gear 80. Rotation of clutch member 122 rotates gear 124 which engages feed gear 84. As explained in relation to the form of the device illustrated in FIG. 2, the gear ratio driving feed gear 84 is slightly different from the gear ratio driving spindle gear 80 thus feed gear 84 rotates with respect to spindle 72 and being in engagement with the external threads on spindle 72 causes spindle 72 to feed through the spindle gear 80.

To change the feed of spindle 72 button 68 is depressed to disengage clutch assembly 120 and to engage clutch assembly 118 as hereinafter explained. The drive connection to feed gear 84 therefore is taken off the main gear train by clutch member 126 engaging clutch gear 98. Clutch member 126 drives gear 128 which through gear 124 drives feed gear 84. This will drive the feed gear 84 at a different rate of speed, for example, faster and thereby cause spindle 72 to feed downwardly a greater amount for each revolution of the spindle.

As in the other form of the invention, the form shown in FIGS. 3 and 4 provides a dwell period after stop collar 76 has engaged thrust bearing 130 during which spindle 72 makes several revolutions without feeding downwardly which in drilling allows the tool T to clean up the hole it is drilling. Further, the engagement of stop collar 76 with thrust bearing 130 causes the rapid retraction of spindle 72 after the dwell period.

When stop collar 76 engages thrust bearing 130 with the clutch assemblies positioned as shown in FIG. 4, feed gear 84 rotates at the same speed as spindle gear 80. This causes clutch member 122 to be cammed upwardly until the ball 32 disengages from the detent 134 in button 70. Thereafter spring 136 urges clutch member 122 upwardly so that its upper projections or teeth 138 engage in the recesses 140 formed in locking member 142. This prevents clutch member 122, gear 124 and feed gear 84 from rotating and with the continued rotation of spindle 72, the spindle 72 is rapidly retracted from the extended position.

A means is provided to allow the change in feed without causing the clutch member 122 to become locked in member 142. The rocker arm 144 which is pivotally mounted to the housing H by the pin 146 engages at one end in the locking member 142 and at the other end in button 68. Thus when button 68 is depressed to change the feed, locking member 142 and button 70 are moved outwardly to allow clutch member 122 to disengage from clutch gear 100 without the teeth 138 on clutch member 122 engaging within the recesses 140 in locking member 142. The button 68 includes the detent 148 which is positioned so that ball 150 engages therein when button 68 is in its depressed position to hold the clutch assembly 118 in its engaged position. The rocker arm 144 moves both locking member 142 and button 70 outwardly when button 68 is pushed inwardly. As explained, this outward movement of locking member 142 and button 70 allows clutch assembly 120 to disengage but prevents the locking engagement of clutch member 122 to locking member 142.

The automatic retraction and dwell features apply even when the clutch assembly 118 is engaged and the clutch assembly 120 is disengaged. With clutch assembly 118 engaged, the downward or feeding movement of spindle 72 is stopped by the engagement of stop collar 76 on thrust bearing 130. This causes feed gear 84 to rotate at the same rate as the spindle 72 which in turn causes the clutch member 126 to be cammed out of engagement with clutch gear 98. The disengagement of clutch member 126 from clutch gear 98 takes several revolutions of spindle 72 thereby providing the dwell period. With the disengagement as described the spring 152 moves the clutch member 126 to its uppermost position which moves button 68 outwardly. The rocker arm 144 translates this outward movement of button 68 to move locking member 142 inwardly whereby teeth 138 on clutch member 122 engage with the recesses 140 in locking member 142. This engagement as previously explained locks feed gear 84 movement to cause spindle 72 to retract at a much greater rate than its feeding rate.

. The clutch member 154 shown in FIG. 5 is typical of the clutch members shown in FIGS. 2 and 4 and is shown to explain the camming disengagement of the clutch member which provides automatic retraction only after a predetermined dwell period. The clutch member 154 includes a body 156 having an outwardly extending flange 158, an upper external gear 160 and the upwardly extending projections or teeth 162. While not shown, the body 156 includes a bore in which the spring which actuates the clutch member may be positioned as shown in FIGS. 2 and 4. The flange 158 includes a plurality of lugs or cam-shaped teeth 164 which are adapted to engage with complementary shaped lugs or teeth on the clutch gear with which the clutch member coacts. The teeth [64 have sloping sides 166 so that the clutch member 154 may be cammed out of engagement with its clutch gear whenever it rotates at a slightly different rate than its clutch gear. The depth of teeth 164 and the angle of the sides 166 together with the difference in the rate of rotation determine the length of the dwell period.

From the foregoing it can be seen that the present invention provides an improved tool actuating device which controls both the speed and feed of a tool when driven by a suitable motor and further provides a dwell period after the feeding has proceeded to its desired limit before the tool is retracted. One form of the invention provides a variation of both speed and feed wherein the variations are independent from each other in the sense that the change of feed does not change the speed but when the speed is changed, the feed is changed.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated, construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

lclaim:

l. A tool actuating device comprising:

a housing;

a spindle mounted within said housing and adapted to support a tool;

a first gear rotatably supported within said housing in surrounding relationship to said spindle;

means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle through said first gear;

a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle;

a gear train for driving said first gear whereby said spindle is rotated;

a clutch member having two positions;

means releasably retaining said clutch member in one position;

means biasing said clutch member toward the other position;

said clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said clutch member;

said clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position, said second gear is held stationary causing said spindle to retract; and

camming means for initiating gradual movement of said clutch member from said one position to the other position to slowly disengage from said gear train and allow the spindle to dwell in its extended position for a short period of time before being retracted.

2. A device according to claim 1 including:

stop means on said spindle to limit the extension of said spindle in one direction;

said stop means being positioned on said spindle to engage said housing;

engagement of said stop means with said housing preventing further axial movement of said spindle and causing said clutch member to disengage from said gear train by unseating said retaining means.

3. A tool actuating device comprising;

a housing;

a spindle mounted within said housing and adapted to support a tool;

a first gear rotatably supported within said housing in surrounding relationship to said spindle;

means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle through said first gear;

a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle;

a gear train for driving said first gear whereby said spindle is rotated;

a clutch member having two positions;

means releasably retaining such clutch member in one position;

means biasing said clutch member toward the other position;

said clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said clutch member;

said clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position, said second gear is held stationary causing said spindle to retract;

the movement of said clutch member from said one position to the other position slowly disengaging from said gear train to allow the spindle to dwell in its extended position for a short period of time before being retracted;

a clutch connected in said gear train;

actuating means for moving said clutch between positions;

first gearing drivingsaid clutch; and

a second gearing connected for driving said gear train when said clutch is disengaged;

said clutch in one position connecting said first gearing to said gear train to provide a first gear ratio to said spindle gear and in its other position connecting said second gearing to said gear train to provide a different gear ratio to said spindle gear whereby the rate of rotation of said spindle may be controlled by operation of said actuating means to move said clutch to the position in which it provides the desired rate of rotation of said spindle.

4. A device according to claim 3 including:

a second clutch member coacting with said first clutch member;

said second clutch member being connectable into said gear train to change the rate of rotation of said first clutch member and said second gear; and

means for actuating said second clutch member;

actuation of said second clutch member into engagement with said gear train disengaging said first clutch member from said gear train and holding said first clutch member out of engagement with said housing to vary the feed rate of said spindle.

5. A tool actuating device comprising:

a housing;

a spindle mounted within said housing and adapted to support a tool;

a first gear rotatably supported within said housing in sur rounding relationship to said spindle;

means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle through said first gear;

a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle;

a gear train for driving said first gear whereby said spindle is rotated;

a first clutch member having two positions;

means releasably retaining said first clutch member in one position;

said first clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said first clutch member;

said first clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position said second gear is held stationary causing said spindle to retract;

the movement of said first clutch member from said one position to the other position slowly disengaging from said gear train to allow the spindle to dwell in its extended position for a short period of time before being retracted;

a second clutch member coacting with said first clutch member;

said second clutch member being connectable into said gear train to change the rate of rotation of said first clutch member and said second gear; and

means for actuating said second clutch member;

actuation of said second clutch member into engagement with said gear train disengaging said first clutch member from said gear train and holding said first clutch member out of engagement with said housing to vary the feed rate of said spindle.

6. A device according to claim 5 including:

a rocker arm pivotally mounted in said housing;

one end of said rocker connected to said first clutch member and the other end connected to said second clutch member whereby engagement of one of said clutch members with said gear train causes the other of said clutch members to disengage from said gear train.

7. A device according to claim 6 including:

a first button mounted in said housing and adapted to engage and actuate said first clutch member; and

a second button mounted in said housing and adapted to engage and actuate said second clutch member; said rocker arm connecting said buttons whereby inward movement of one results in outward movement of the other;

movement of said first button inwardly engaging said first clutch member with said gear train and disengaging said second clutch member from said gear train;

movement of said second button inwardly engaging said second clutch member with said gear train and disengaging said first clutch member from said gear train. 8. A device according to claim 7 including; a locking member movably mounted within said housing between said first clutch member and said first button;

said locking member including means for retaining said first clutch member stationary when both clutch members are disengaged from said gear train.

9. A device according to claim 8 wherein said locking member is movable in said housing with respect to said first button responsive to the disengagement of said second clutch member to engage said first clutch member and lock said first clutch member against rotation to retract said spindle.

10. A device according to claim 1 wherein said clutch member includes:

a body;

an outwardly extending flange;

tapered teeth extending axially from the outer portion of said flange to engage with said gear train; and

projections extending outward from one end of said body for engaging with recesses in said housing to retain said clutch member against rotation.

ll. A device according to claim 1 wherein said clutch member includes camming teeth for providing the engagement between said clutch member and said gear train and gradual disengagement when said clutch member rotates at a different rate than the engaged portion of said gear train.

12. A device according to claim 3 wherein said clutch includes;

a sprag clutch;

a clutch gear connected to said sprag clutch;

a clutch member adapted to engage said clutch gear;

an output gear in said gear train and engaged with both said sprag clutch and said clutch member whereby the speed of rotation of said spindle is preselected by the positioning of said clutch member; and

means for actuating said clutch member into and from engagement with said clutch gear;

engagement of said clutch member with said clutch gear functioning to bypass said sprag clutch in driving said gear train to allow control of the spindle speed.

13. As a subcombination with a tool actuating device including a gear train and a housing, a clutch member comprising;

a body;

an outwardly extending flange;

tapered teeth extending axially from the outer portion of said flange to engage and cammingly disengage said gear train; and

projections extending outward from one end of said body and effective when said teeth disengage said gear train for engaging with recesses in said housing to retain said body against rotation; 

1. A tool actuating device comprising: a housing; a spindle mounted within said housing and adapted to support a tool; a first gear rotatably supported within said housing in surrounding relationship to said spindle; means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle through said first gear; a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle; a gear train for driving said first gear whereby said spindle is rotated; a clutch member having two positions; means releasably retaining said clutch member in one position; means biasing said clutch member toward the other position; said clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said clutch member; said clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position, said second gear is held stationary causing said spindle to retract; and camming means for initiating gradual movement of said clutch member from said one position to the other position to slowly disengage from said gear train and allow the spindle to dwell in its extended position for a short period of time before being retracted.
 2. A device according to claim 1 including: stop means on said spindle to limit the extension of said spindle in one direction; said stop means being positioned on said spindle to engage said housing; engagement of said stop means with said housing preventing further axial movement of said spindle and causing said clutch member to disengage from said gear train by unseating said retaining means.
 3. A tool actuating device comprising; a housing; a spindle mounted within said housing and adapted to support a tool; a first gear rotatably supported within said housing in surrounding relationship to said spindle; means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle thrOugh said first gear; a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle; a gear train for driving said first gear whereby said spindle is rotated; a clutch member having two positions; means releasably retaining such clutch member in one position; means biasing said clutch member toward the other position; said clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said clutch member; said clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position, said second gear is held stationary causing said spindle to retract; the movement of said clutch member from said one position to the other position slowly disengaging from said gear train to allow the spindle to dwell in its extended position for a short period of time before being retracted; a clutch connected in said gear train; actuating means for moving said clutch between positions; first gearing driving said clutch; and a second gearing connected for driving said gear train when said clutch is disengaged; said clutch in one position connecting said first gearing to said gear train to provide a first gear ratio to said spindle gear and in its other position connecting said second gearing to said gear train to provide a different gear ratio to said spindle gear whereby the rate of rotation of said spindle may be controlled by operation of said actuating means to move said clutch to the position in which it provides the desired rate of rotation of said spindle.
 4. A device according to claim 3 including: a second clutch member coacting with said first clutch member; said second clutch member being connectable into said gear train to change the rate of rotation of said first clutch member and said second gear; and means for actuating said second clutch member; actuation of said second clutch member into engagement with said gear train disengaging said first clutch member from said gear train and holding said first clutch member out of engagement with said housing to vary the feed rate of said spindle.
 5. A tool actuating device comprising: a housing; a spindle mounted within said housing and adapted to support a tool; a first gear rotatably supported within said housing in surrounding relationship to said spindle; means connecting said first gear to said spindle for rotation with said spindle and to allow axial travel of said spindle through said first gear; a second gear rotatably supported within said housing in surrounding threaded relationship to said spindle; a gear train for driving said first gear whereby said spindle is rotated; a first clutch member having two positions; means releasably retaining said first clutch member in one position; said first clutch member being driven by said gear train in said one position and engaging said housing in the other position to prevent rotation of said first clutch member; said first clutch member being connected to said second gear in both positions thereof whereby when in said one position said second gear rotates at a different rate than said spindle to feed said spindle through said housing and when in said other position said second gear is held stationary causing said spindle to retract; the movement of said first clutch member from said one position to the other position slowly disengaging from said gear train to allow the spindle to dwell in its extended position for a short period of time before being retracted; a second clutch member coacting with said first clutch member; said second clutch member being connectable into said gear train to change the rate of rotation of said first clutch member and said Second gear; and means for actuating said second clutch member; actuation of said second clutch member into engagement with said gear train disengaging said first clutch member from said gear train and holding said first clutch member out of engagement with said housing to vary the feed rate of said spindle.
 6. A device according to claim 5 including: a rocker arm pivotally mounted in said housing; one end of said rocker connected to said first clutch member and the other end connected to said second clutch member whereby engagement of one of said clutch members with said gear train causes the other of said clutch members to disengage from said gear train.
 7. A device according to claim 6 including: a first button mounted in said housing and adapted to engage and actuate said first clutch member; and a second button mounted in said housing and adapted to engage and actuate said second clutch member; said rocker arm connecting said buttons whereby inward movement of one results in outward movement of the other; movement of said first button inwardly engaging said first clutch member with said gear train and disengaging said second clutch member from said gear train; movement of said second button inwardly engaging said second clutch member with said gear train and disengaging said first clutch member from said gear train.
 8. A device according to claim 7 including; a locking member movably mounted within said housing between said first clutch member and said first button; said locking member including means for retaining said first clutch member stationary when both clutch members are disengaged from said gear train.
 9. A device according to claim 8 wherein said locking member is movable in said housing with respect to said first button responsive to the disengagement of said second clutch member to engage said first clutch member and lock said first clutch member against rotation to retract said spindle.
 10. A device according to claim 1 wherein said clutch member includes: a body; an outwardly extending flange; tapered teeth extending axially from the outer portion of said flange to engage with said gear train; and projections extending outward from one end of said body for engaging with recesses in said housing to retain said clutch member against rotation.
 11. A device according to claim 1 wherein said clutch member includes camming teeth for providing the engagement between said clutch member and said gear train and gradual disengagement when said clutch member rotates at a different rate than the engaged portion of said gear train.
 12. A device according to claim 3 wherein said clutch includes; a sprag clutch; a clutch gear connected to said sprag clutch; a clutch member adapted to engage said clutch gear; an output gear in said gear train and engaged with both said sprag clutch and said clutch member whereby the speed of rotation of said spindle is preselected by the positioning of said clutch member; and means for actuating said clutch member into and from engagement with said clutch gear; engagement of said clutch member with said clutch gear functioning to bypass said sprag clutch in driving said gear train to allow control of the spindle speed.
 13. As a subcombination with a tool actuating device including a gear train and a housing, a clutch member comprising; a body; an outwardly extending flange; tapered teeth extending axially from the outer portion of said flange to engage and cammingly disengage said gear train; and projections extending outward from one end of said body and effective when said teeth disengage said gear train for engaging with recesses in said housing to retain said body against rotation. 